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From: Florian Fainelli <f.fainelli@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: bcm-kernel-feedback-list@broadcom.com,
	Florian Fainelli <f.fainelli@gmail.com>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Jean Delvare <jdelvare@suse.com>,
	Guenter Roeck <linux@roeck-us.net>,
	linux-arm-kernel@lists.infradead.org,
	linux-hwmon@vger.kernel.org (open list:HARDWARE MONITORING)
Subject: [PATCH v4 2/2] hwmon: scmi: Scale values to target desired HWMON units
Date: Wed,  8 May 2019 10:00:35 -0700	[thread overview]
Message-ID: <20190508170035.19671-3-f.fainelli@gmail.com> (raw)
In-Reply-To: <20190508170035.19671-1-f.fainelli@gmail.com>

If the SCMI firmware implementation is reporting values in a scale that
is different from the HWMON units, we need to scale up or down the value
according to how far appart they are.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/hwmon/scmi-hwmon.c | 46 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/hwmon/scmi-hwmon.c b/drivers/hwmon/scmi-hwmon.c
index a80183a488c5..4399372e2131 100644
--- a/drivers/hwmon/scmi-hwmon.c
+++ b/drivers/hwmon/scmi-hwmon.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/hwmon.h>
+#include <linux/limits.h>
 #include <linux/module.h>
 #include <linux/scmi_protocol.h>
 #include <linux/slab.h>
@@ -18,6 +19,47 @@ struct scmi_sensors {
 	const struct scmi_sensor_info **info[hwmon_max];
 };
 
+static inline u64 __pow10(u8 x)
+{
+	u64 r = 1;
+
+	while (x--)
+		r *= 10;
+
+	return r;
+}
+
+static int scmi_hwmon_scale(const struct scmi_sensor_info *sensor, u64 *value)
+{
+	s8 scale = sensor->scale;
+	u64 f;
+
+	switch (sensor->type) {
+	case TEMPERATURE_C:
+	case VOLTAGE:
+	case CURRENT:
+		scale += 3;
+		break;
+	case POWER:
+	case ENERGY:
+		scale += 6;
+		break;
+	default:
+		break;
+	}
+
+	f = __pow10(abs(scale));
+	if (f == U64_MAX)
+		return -E2BIG;
+
+	if (scale > 0)
+		*value *= f;
+	else
+		*value = div64_u64(*value, f);
+
+        return 0;
+}
+
 static int scmi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
 			   u32 attr, int channel, long *val)
 {
@@ -29,6 +71,10 @@ static int scmi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
 
 	sensor = *(scmi_sensors->info[type] + channel);
 	ret = h->sensor_ops->reading_get(h, sensor->id, false, &value);
+	if (ret)
+		return ret;
+
+	ret = scmi_hwmon_scale(sensor, value);
 	if (!ret)
 		*val = value;
 
-- 
2.17.1


  parent reply	other threads:[~2019-05-08 17:00 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-08 17:00 [PATCH v4 0/2] " Florian Fainelli
2019-05-08 17:00 ` [PATCH v4 1/2] firmware: arm_scmi: Fetch and store sensor scale Florian Fainelli
2019-05-08 18:33   ` Guenter Roeck
2019-05-08 17:00 ` Florian Fainelli [this message]
2019-05-08 18:32   ` [PATCH v4 2/2] hwmon: scmi: Scale values to target desired HWMON units Guenter Roeck
2019-05-08 18:34     ` Florian Fainelli
2019-05-08 19:40       ` Guenter Roeck

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